Analysis Communication on the Bridge The OOW represents the master and is essentially responsible at all times for the safety of the ship. S/he should ensure that an effective visual and auditory watch is maintained at all times. The alarm for the No1 steering gear power unit went off four times. Although alarms may go off frequently on the bridge, each and every one must be investigated to determine the cause of the failure. The OOW reportedly advised the pilot as soon as the first alarm sounded on the bridge, but, according to the pilot, he was not advised. It is the responsibility of the crew to ensure that the pilot has understood all information pertaining to the conduct of the vessel. This allows the bridge team to analyze the situation and make decisions that are necessary for the proper conduct of the ship. Any unexpected change that could alter the way the navigation is planned and executed can then be discussed by all bridge team members. Bridge resource management essentially consists of efficiently utilizing all available resources in order to promote safe transportation. Emergency Stop Control System A computerized system in the emergency stop control system maximizes the effectiveness of speed changes in an emergency situation and prevents overloading of main-engine and auxiliary components. In the seconds following the steering gear failure, the engine telegraph was set to the stop position, then to full astern. The main engine took 155s to stop and then engaged in reverse mode. Had the telegraph been operated so as to make use of the emergency stop feature, the main engine would have stopped in about 135s, that is, approximately 20s sooner. The main-engine response time for emergency crash stops was posted on the bridge, but the crew did not know how to operate the AutoChief4system. That information could be found in the operations manual. In this occurrence, reducing the stopping time by 20s would not have prevented the occurrence. Nonetheless, good working knowledge of a vessel's components enhances a crew's confidence and promotes optimal operations. Transfer of Steering Gear Control Mode The crew seemed to be familiar with navigation equipment, including the steering gear control system and emergency procedures. In the event of a rudder failure on the Fossnes, the crew was required to switch from one control mode to the other (that is, from FU control mode to NFU control mode). The NFU control mode was tried in the moments following the rudder failure, but this mode transfer did not produce the desired effect. The investigation showed that the No2 power unit was operating during the occurrence. Moreover, the No2 power unit did not trigger any alarms or trip the No2 circuit breaker. When the chief engineer and the electrician arrived, the No2 power unit was operating normally. Hence, NFU control mode should have been operationally ready throughout the occurrence. Since the vessel was a short distance from shore, the crew was under pressure to correct the situation quickly. It is possible that the steering gear control mode switch was carried out but that the crew did not leave it in the NFU mode long enough. A certain period of time is required for the system to activate and for the vessel to respond to the change in rudder angle. The rudder remained to starboard and, despite all efforts, the vessel went aground. Had the power failure affected the rudder indicator system, the transfer to the other power source would have been automatic, given that the selector switch was in position No3. The steering gear control system does not have this type of protection, nor is it required under SOLAS. Steering Gear Electrical System When the breaker trips, it will cut power to all circuits connected to it because the steering gear control circuit is connected to the main breaker output of the power unit's power circuit. The supply circuit of the ship's steering gear control was in compliance with SOLAS requirements. However, although it was in compliance, the point from which power is taken and the location where the overload device is installed could allow an unanticipated breakdown of the control system in FU mode and NFU mode. A test determined that the sudden tripping of the main breaker results in the de-energizing of the supply line to the No1 power unit and, consequently, a failure of the FU control mode (Figure1). Figure1. Electrical arrangement of steering gear power unit and control circuits. To protect the supply line, the main breaker of power unit No1 has two protection devices: one for short circuits and one for overcurrents. These two types of protection are acceptable pursuant to the SOLAS Convention. After the grounding, the test with a megohmmeter on the electrical components of power unit No1 revealed no evidence that a short circuit had occurred. All indicates that the malfunction of the closure mechanism of the power unit motor contactor, combined with the high starting current following several starts, contributed to an overcurrent exceeding the setting for long-delay protection. Hence, this excessive overcurrent tripped the main breaker. The contactor malfunctioned because small pieces of polymer affected the mechanical movement of the contactor. The deterioration of the polymer used to manufacture the spring guide shows the importance of carefully monitoring the condition of parts and the environment in which the parts are intended to be used.5 The degradation of this polymer contributed to the reduction of the theoretical service life of the contactor and created an overcurrent in the supply circuit. Since the three contactors examined had the same defect, the choice of contactors used on board can be questioned. Central Processing Unit The investigation revealed that the wiring of the CPUs, although not a contributing factor in the incident, was contrary to that shown on the drawings. The design drawings show that an individual electrical feeder circuit is to be provided for each CPU, making each system an independent system. The vessel has been wired with a single source of electrical power to both CPUs. Therefore, when that single source was compromised, the redundancy of the system was also compromised. The tripping of the main circuit breaker cut power to the supply line of the No1 power unit and, consequently, resulted in the failure of the FU control mode. At the time of the failure, the rudder was turned to starboard. The crew was unable to restore steering gear control.Findings as to Causes and Contributing Factors The tripping of the main circuit breaker cut power to the supply line of the No1 power unit and, consequently, resulted in the failure of the FU control mode. At the time of the failure, the rudder was turned to starboard. The crew was unable to restore steering gear control. The point from which power is supplied and the point where the overload protection device is installed can allow unexpected failure of the control system. Deterioration of the polymer used to manufacture the spring guide contributed to the malfunction of the contactor. Broader knowledge of the main-engine emergency stop control system would have enabled the crew to instigate astern propulsion sooner.Findings as to Risk The point from which power is supplied and the point where the overload protection device is installed can allow unexpected failure of the control system. Deterioration of the polymer used to manufacture the spring guide contributed to the malfunction of the contactor. Broader knowledge of the main-engine emergency stop control system would have enabled the crew to instigate astern propulsion sooner. A loss of power at the emergency switchboard deactivates all steering gear alarms.Other Findings A loss of power at the emergency switchboard deactivates all steering gear alarms. The TSB sent Marine Safety Information Letter (MSI) 01/01, concerning the contactor defect, to the owner, with copies to the manufacturer, the Administration of the Registry, the shipyard, and the International Association of Classification Societies. The manufacturer, Hydroster, had decided to use other types of contactors as a result of testing new products in 1997. The TSB sent MSI 08/01, concerning the inadequacy of SOLAS regulations on steering gear electrical systems, to Transport Canada. If Transport Canada deems necessary, a submission can be made to the International Maritime Organization. The TSB sent MSI 09/01, concerning the CPU connections that are not in accordance with the approved drawing, to the owner, with copies to the Port State and the classification society.Safety Action The TSB sent Marine Safety Information Letter (MSI) 01/01, concerning the contactor defect, to the owner, with copies to the manufacturer, the Administration of the Registry, the shipyard, and the International Association of Classification Societies. The manufacturer, Hydroster, had decided to use other types of contactors as a result of testing new products in 1997. The TSB sent MSI 08/01, concerning the inadequacy of SOLAS regulations on steering gear electrical systems, to Transport Canada. If Transport Canada deems necessary, a submission can be made to the International Maritime Organization. The TSB sent MSI 09/01, concerning the CPU connections that are not in accordance with the approved drawing, to the owner, with copies to the Port State and the classification society.